The long term objective of the proposed research is to conduct an assessment of the carcinogenic hazard posed to humans who eat freshwater sportfishes. Polycyclic aromatic hydrocarbons (PAH) are organic compounds derived from the combustion of fossil fuels. Many PAH are carcinogenic, and can be found in high concentrations in the sediments of aquatic systems. Organisms that utilize these sediments as a source of food can accumulate carcinogenic compounds within their tissues. One such freshwater fish is the gizzard shad. This fish also comprises a major portion of the diet in many sport fishes. The potential exists, therefore, that carcinogenic materials may enter the human food chain by way of: sediment to sediment-feeding-fish to sport fish to humans. The sport fish chosen for use in these studies is the large-mouth bass. The long term objective will be met by the performance of 3 sets of experiments. The first set of experiments will examine the ability of gizzard shad to accumulate a carcinogenic PAH (benzo(a)pyrene) from the ingestion of artificial sediments dosed with known amounts of the compound. The second set of experiments will examine the uptake, metabolism, and elimination of the same compound by large-mouth bass after ingestion of a defined, non-living food source contaminated with known amounts of benzo(a)pyrene. The third set of experiments will examine the long term uptake and accumulation of benzo(a)pyrene by largemouth bass from the ingestion of gizzard shad that have accumulated this contaminant from eating artificial sediments. The results of all experiments will be used to construct an assessment of the hazard posed to human consumers of largemouth bass.